Replies

1. 
   Rob_Sp | Jan 22, 2024 03:17pm | #1

   You want to keep the area of the ducts the same. A 6" duct is 28 sq.in. the combined area of the two 4" ducts is about 24 sq.in.
   So I would do a 6" drop with a wye at the bottom with two 4" openings for your hose. This should maintain the correct cfm.
   I am assuming you have blast gates at your other outlets.
   I am surprised you are not getting help from Onieda, did they not design your present ductwork system?

1. 
   user-210490 | Jan 22, 2024 04:51pm | #2

   thanks, I was talking to the wrong person at Oneida, technical support was finally able to help which is in line with what you recommend.

2. 
   hotdogman | Jan 22, 2024 11:30pm | #3

   You need to consider the velocity of the air movement at your machines not just volume of air. Velocity is needed to efficiently move the sawdust out of the machines. Your drop to the machines off the main line should be 4 inch diameter pipe with easy access to a blast gate at each. You could go from 6 inch to 5 inch for transition then reduce to use 4 inch with a wye to each machine assuming they are close together. I have a 7 inch line at a cyclone up to a 6 inch and then 5 inch along the ceiling but each drop to the machines on my system is 4 inches back up to a 5 inch carry line at the ceiling. It works great with lots of high velocity air for sawdust removal and no clogging.

3. 
   _mj_ | Jan 23, 2024 08:46am | #4

   Insert a 6"-4" wye in the main line for the drop. To pull straight up 9' you need the velocity as hotdogman says. If you come down with 5" and then reduce you'll have a dead spot in the drop that will tumble material where the velocity changes. That material will drop and clog your gates when you turn off the system.